Linking Issues

[pvelesko]

Using clang17

[ 98%] Linking CXX shared library libopencl-clang.so
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllTargetInfos()':
/opt/install/llvm/16.0/include/llvm/Config/Targets.def:26: undefined reference to `LLVMInitializeX86TargetInfo'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllTargets()':
/opt/install/llvm/16.0/include/llvm/Config/Targets.def:26: undefined reference to `LLVMInitializeX86Target'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllAsmPrinters()':
/opt/install/llvm/16.0/include/llvm/Config/AsmPrinters.def:27: undefined reference to `LLVMInitializeX86AsmPrinter'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllAsmParsers()':
/opt/install/llvm/16.0/include/llvm/Config/AsmParsers.def:27: undefined reference to `LLVMInitializeX86AsmParser'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllTargetMCs()':
/opt/install/llvm/16.0/include/llvm/Config/Targets.def:26: undefined reference to `LLVMInitializeX86TargetMC'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `Compile':
/home/pvelesko/opencl-clang/opencl_clang.cpp:339: undefined reference to `llvm::writeSpirv(llvm::Module*, SPIRV::TranslatorOpts const&, std::ostream&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/opencl-clang.dir/build.make:223: libopencl-clang.so.16] Error 1
make[1]: *** [CMakeFiles/Makefile2:258: CMakeFiles/opencl-clang.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

Using clang16

[ 98%] Linking CXX shared library libopencl-clang.so
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `Compile':
/home/pvelesko/opencl-clang/opencl_clang.cpp:321: undefined reference to `llvm::writeSpirv(llvm::Module*, SPIRV::TranslatorOpts const&, std::ostream&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/opencl-clang.dir/build.make:224: libopencl-clang.so.17rc] Error 1
make[1]: *** [CMakeFiles/Makefile2:258: CMakeFiles/opencl-clang.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

[pvelesko]

I had to recompile LLVM to use dynamic linking (not default) which fixed the issue. Maybe a note somewhere in the readme?

[wenju-he]

@pvelesko could you please provide build step for the above failure so that we can reproduce?
Are you using out-of-tree build, i.e. build LLVM and SPIR-V Translator first and then build opencl-clang?

[pvelesko]

Using a pre-built LLVM + SPIR-V Translator, then try for opencl-clang. Here is the script used to configure LLVM:

#!/bin/bash

# check arguments
if [ $# -ne 2 ]; then
  echo "Usage: $0 <version> <install_dir>"
  echo "version: LLVM version 15, 16, 17"
  exit 1
fi

# if an error is enountered, exit
set -e

VERSION=$1
INSTALL_DIR=$2
export LLVM_DIR=`pwd`/llvm-project/llvm

# check if llvm-project exists, if not clone it
if [ ! -d llvm-project ]; then
  git clone git@github.com:CHIP-SPV/llvm-project.git -b chipspv-llvm-${VERSION}-patches --depth 1
  cd ${LLVM_DIR}/projects
  git clone git@github.com:CHIP-SPV/SPIRV-LLVM-Translator.git -b chipspv-llvm-${VERSION}-patches --depth 1
  cd ${LLVM_DIR}
else
  # Warn the user, error out
  echo "llvm-project directory already exists. Assuming it's cloned from chipStar."
  cd ${LLVM_DIR}
  # check if already on the desired branch 
  if [ `git branch --show-current` == "chipspv-llvm-${VERSION}-patches" ]; then
    echo "Already on branch chipspv-llvm-${VERSION}-patches"
  else
    echo "Switching to branch chipspv-llvm-${VERSION}-patches"
    git br -D chipspv-llvm-${VERSION}-patches &> /dev/null
    git fetch origin chipspv-llvm-${VERSION}-patches:chipspv-llvm-${VERSION}-patches
    git checkout chipspv-llvm-${VERSION}-patches
  fi
  cd ${LLVM_DIR}/projects/SPIRV-LLVM-Translator
  # check if already on the desired branch
  if [ `git branch --show-current` == "chipspv-llvm-${VERSION}-patches" ]; then
    echo "Already on branch chipspv-llvm-${VERSION}-patches"
  else
    echo "Switching to branch chipspv-llvm-${VERSION}-patches"
    git br -D chipspv-llvm-${VERSION}-patches &> /dev/null
    git fetch origin chipspv-llvm-${VERSION}-patches:chipspv-llvm-${VERSION}-patches
    git checkout chipspv-llvm-${VERSION}-patches
  fi
  cd ${LLVM_DIR}
fi

# check if the build directory exists, if not create it
if [ ! -d build_$VERSION ]; then
  mkdir build_$VERSION
  cd build_$VERSION
else
  # Warn the user, error out
  echo "Build directory build_$VERSION already exists, please remove it and re-run the script"
  exit 1
fi

cmake ../  \
  -DCMAKE_INSTALL_PREFIX=${INSTALL_DIR} \
  -DCMAKE_BUILD_TYPE=Release \
  -DLLVM_ENABLE_PROJECTS="clang;openmp" \
  -DLLVM_TARGETS_TO_BUILD=X86

[wenju-he]

I'll take a look.

[wenju-he]

On container ubuntu 22.04 and 16 branch I reproduced the same error if llvm and llvm-spirv is built to static libraries:

[ 98%] Linking CXX shared library libopencl-clang.so
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `Compile':
opencl_clang.cpp:(.text+0x14c4): undefined reference to `llvm::writeSpirv(llvm::Module*, SPIRV::TranslatorOpts const&, std::ostream&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllTargetInfos()':
opencl_clang.cpp:(.text._ZN4llvm24InitializeAllTargetInfosEv[_ZN4llvm24InitializeAllTargetInfosEv]+0x9): undefined reference to `LLVMInitializeX86TargetInfo'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllTargets()':
opencl_clang.cpp:(.text._ZN4llvm20InitializeAllTargetsEv[_ZN4llvm20InitializeAllTargetsEv]+0xe): undefined reference to `LLVMInitializeX86Target'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllTargetMCs()':
opencl_clang.cpp:(.text._ZN4llvm22InitializeAllTargetMCsEv[_ZN4llvm22InitializeAllTargetMCsEv]+0x9): undefined reference to `LLVMInitializeX86TargetMC'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllAsmPrinters()':
opencl_clang.cpp:(.text._ZN4llvm24InitializeAllAsmPrintersEv[_ZN4llvm24InitializeAllAsmPrintersEv]+0x9): undefined reference to `LLVMInitializeX86AsmPrinter'
/usr/bin/ld: CMakeFiles/opencl-clang.dir/opencl_clang.cpp.o: in function `llvm::InitializeAllAsmParsers()':
opencl_clang.cpp:(.text._ZN4llvm23InitializeAllAsmParsersEv[_ZN4llvm23InitializeAllAsmParsersEv]+0x9): undefined reference to `LLVMInitializeX86AsmParser'
collect2: error: ld returned 1 exit status
gmake[2]: *** [CMakeFiles/opencl-clang.dir/build.make:223: libopencl-clang.so.16] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:258: CMakeFiles/opencl-clang.dir/all] Error 2
gmake: *** [Makefile:136: all] Error 2

[wenju-he]

The above build fail could be fixed using llvm-config, same as in #454 (comment)

execute_process(COMMAND llvm-config --libnames all OUTPUT_VARIABLE ALL_LIBS)
string(REPLACE "lib" "" ALL_LIBS1 ${ALL_LIBS})
string(REPLACE ".a" "" ALL_LIBS2 ${ALL_LIBS1})
string(STRIP ${ALL_LIBS2} ALL_LIBS3)
string(REPLACE " " ";" ALL_LIBS4 ${ALL_LIBS3})
list(APPEND OPENCL_CLANG_LINK_LIBS ${ALL_LLVM_LIBS} ${ALL_LIBS4} LLVMSPIRVLib)

[wenju-he]

Propose a fix PR to use llvm-config: #490